Colgate Directory

Randy Fuller

Randy Fuller's Research

My research interests are primarily in stream ecology and have spanned all trophic levels from how light influences algae and thus bacteria to how algal abundance affects macroinvertebrates in forested versus agricultural streams. In addition, I have examined the degree of overlap in diets of fish versus invertebrate predators that share prey pools in the same stream reaches. More recently my research has focused on the impacts of frequent flooding caused by recreational releases of water from a reservoir to support a whitewater rafting industry. Also, I am collaborating with several other aquatic and terrestrial scientists examining how the long-term loss of calcium from Adirondack forest soils is impacting both terrestrial and aquatic communities. Students are an integral part of my research and I rely heavily on them to maintain an active research program.

Current Projects in Stream Ecology

I have several projects that my students are working on currently. Two of these are located in the Adirondack Mountains. One project involves determining the impact of water releases from the Abanakee Dam into the Indian River to support a white-water rafting enterprise. Releases raise the water level in the Indian River by 0.4-0.5m four days each week from April through early October.

These releases scour much of the river bottom and result in a highly disturbed system. In collaboration with a stream geomorphologists (Dr. Martin Doyle, Duke University), we have examined the effects of variation in discharge in the Indian River and compared this riverine community to communities in other local rivers to assess the relative impacts of these frequent releases of water on periphyton and macroinvertebrate communities in the Indian River, the Upper Hudson River above and below its confluence with the Indian River (the latter site would also be influenced by the water releases) and the Cedar and Boreas Rivers. Several papers have already been published stemming from this research.

The other project in the Adirondack Mountains is a long-term collaborative study that began with support from NSF and involved initially two geologists (Dr. R. April, Colgate University and Dr. M. Hluchy, Alfred University) and a small mammal ecologist (Dr. T. McCay). We examined Ca depletion in Adirondack forest soils due to acid deposition and its impact on terrestrial and aquatic food webs. While there has been a decrease in sulfate deposition in the Adirondacks after the advent of the 1990 Clean Air Act Amendments, there has been little improvement in either terrestrial or aquatic ecosystems and some research suggests that Ca depletion in soils may be a primary factor in their slow recovery. My part of this project involves examining the impact of episodic acidification events on stream communities. We understand the effects of chronic acidification on stream communities, but there is less information on the relative impacts of episodic events resulting from pulses of acid added during snowmelt and rainstorm events. These would be perturbations to the system and could act as a disturbance event not only because of the increased discharge, but also because of the rapid pH decline during these high flow events. Our results have documented a further loss of calcium from Adirondack forest soils that were sampled in the 1980’s, and there are clear impacts on communities in episodically acidified streams. This research has resulted in a further collaboration of scientists from Cornell University, SUNY-College of Environmental Science and Forestry and the USGS office in Troy, NY. We are initiating a long-term study of tributaries to Honnedaga Lake some of which are chronically acidic and others are episodically acidic. Once we have characterized thecommunities in these streams and the plant communities in their drainage basins, we will add lime directly to 2 streams and compare their chemical and biotic changes to control streams that were not manipulated. In a second set of manipulations, we will add lime to a whole watershed and again compare both terrestrial and aquatic community responses to this manipulation with corresponding communities in adjacent drainage basins.

Research on Local Lakes

We have studied local lakes and their tributaries to examine nutrient inputs and their influence on lake water quality. Of the lakes studied so far, we have identified some tributaries to be strongly influenced by agricultural inputs and these appear to have influenced lake productivity. One lake has no cottages and low nutrient inputs from its tributary, but still had the highest productivity of any of the lakes examined largely because of a resident goose population that contributes significant quantities of nutrients to the lake. We are continuing this project by adding more lakes to the survey. Our goal is to better understand what sources of nutrients might be most important for a particular lake in order to better focus management plans for any one lake. The lakes are different in basin shape, depth and area characteristics, but to date these morphometric features are less important in determining water quality than the nutrient sources and loading to the lakes.